Field of the Invention
The invention lies in the semiconductor technology and semiconductor processing fields. More specifically, the present invention relates to a semiconductor chip which is partially provided, after mounting on a chip carrier, with an encapsulation of the connection pads and/or the bonding wires. The encapsulation is referred to as a housing. Specific active regions of the top side remain free. The invention also pertains to a production method for such a housing.
The active circuits of semiconductor chips are usually connected to a chip carrier via the connection pads, referred to as bonding pads, the semiconductor chip being mounted on the chip carrier. Customary connection methods, for example, are wire bonding, in which the connection pads of the semiconductor chip and the connection pads of the chip carrier are connected to one another in pairs by soldered-on wires, and flip-chip bonding, in which the top-side contacts of the semiconductor chip are fitted directly on assigned contact areas of the chip carrier.
These connections are normally good enough in electrical terms, but not stable enough in mechanical terms. For this reason, a mechanical protection of the semiconductor chip, in particular for the electrical connections, is usually provided. Therefore, the semiconductor chip is usually enclosed by injection-molding in a potting compound or coverage with an encapsulation compound in a so-called housing. In this case, all connections between the chip and the chip carrier and at least the entire active region of the chip are encapsulated.
If specific active regions of the semiconductor chip are not permitted to be encapsulated for reasons of the mode of operation, e.g. the bearing area for a finger in a fingerprint sensor, the housing can be limited to the remaining regions of the top side of the semiconductor chip. Since the bonding pads are generally situated close to the active regions on the chips and the bonding pads must always be encapsulated, what is required is an enclosure of the chip in a housing in which closely adjacent regions of the top side of the chip are in some instances left free and in some instances encapsulated by the housing.
That can be done by fitting, on the chip carrier provided with the chip, a barrier between those portions of the top side of the chip which are intended to be covered and the remaining portions of the top side of the chip, which are intended to remain free. During the application of the potting compound or encapsulation compound to the bonding pads and wire connections, this barrier prevents the potting compound or encapsulation compound from flowing into those active chip regions which are intended to remain free. The barrier can subsequently be removed. However, the additional fitting of a barrier of this type requires additional effort and thus additional costs; in particular cases, a selective encapsulation of the semiconductor chip can thus be realized only with difficulty, or not at all.